J jmckmills New member Joined Feb 17, 2009 Messages 1 Feb 17, 2009 #1 I need to find the perimeter of an equilateral triangle inside a circle with a radius of 6....can you help me get started?
I need to find the perimeter of an equilateral triangle inside a circle with a radius of 6....can you help me get started?
D Deleted member 4993 Guest Feb 17, 2009 #2 jmckmills said: I need to find the perimeter of an equilateral triangle inside a circle with a radius of 6....can you help me get started? Click to expand... Sketch the problem. Let the triangle be ABC - and the center of the circle is O. Join OA, OB and OC. Then OA = OB = OC = ???? How much is angle ABC = ???? angle OBC = 1/2(angle ABC ) = ??? Now calculate side BC = 2 * OB * cos(OBC) = AB = CA Perimeter = AB + BC + CA
jmckmills said: I need to find the perimeter of an equilateral triangle inside a circle with a radius of 6....can you help me get started? Click to expand... Sketch the problem. Let the triangle be ABC - and the center of the circle is O. Join OA, OB and OC. Then OA = OB = OC = ???? How much is angle ABC = ???? angle OBC = 1/2(angle ABC ) = ??? Now calculate side BC = 2 * OB * cos(OBC) = AB = CA Perimeter = AB + BC + CA
